84 CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 



blood have yielded pure cultures of micrococci. A fact of great im. 

 portance is that uo pure cultures of bacilli have been obtained, and that 

 where but a siugle species of organism has multiplied this has invaria- 

 bly been a micrococcus. 



Having obtained such results from my investigations, and having re- 

 peated them over and over again, and coufirmed them with virus from 

 various parts of the country, I cannot but conclude that swine i)lague 

 is due to a micrococcus, and that the disease produced by Dr. Klein's 

 cultivated bacilli was a form of septiciemia. And this conclusion is 

 contirined by the short peri();l of incub.itiou in his cases, and the fact 

 that many of his animals showed no signs of disease other than a slight 

 rise of temperature and an enlargement and congestion of the lymph 

 glands. 



The following record of experiments contains the most important of 

 those which have been made since my last report, and is a continuation 

 of the evidence upon which the above statements have been made: 



Experiment No. 1. — Two pigs were inoculated June 28, 1883, with 

 virus dried on quills and sent from Indiana. It was obtained by killing 

 a sick pig and immediately dipping the quills in peritoneal and pleural 

 effusion and the exudation liquid from the lungs, yud drying this after 

 the manner practiced for preservation of vaccine lymph. In this case 

 the animal from which the virus was obtained ('• t not have a very 

 severe form of the disease. For inoculation the v rus on three or four 

 quills was rubbed up with 2<'t- of salt solution and injected under the 

 skin of thigh. The fourth day (July 2) there was elevated temperature 

 (102AO and lOo^o F.) and slight redness at the point of inoculation. The 

 fifth day there was diffused redness on the inner side of both thighs, 

 an eruption of small pai)ul;e on the thin parts of the skin and an in- 

 creased elevation of temperature (103fo and 1()4a° F.). July 5 to 9 

 the temperature remaiued at or above 105° with one, and reached its 

 highest point on the 7th, beiug then 10o|°, and the eruption was very 

 plain and extended over the greater part of the surface of the body. 

 From this time they began to improve, and in neither case was the 

 disease fatal. 



This was one of a number of inoculation experiments made to obtain 

 a reliable virus for experimental purposes, and is recorded to illustrate 

 the above remarks in regard to the i)eriod of incubation. 



Experiment No. 2. — Four hogs were inoculated July 7, with virus 

 also from Indiana, and preserved in the same way as the other, but was 

 obtained from an outbreak which was much more virulent and fatal. 

 This was also suspended in salt solution and injected hypodermically in 

 the dose 2«c- to ^co. at the inner si<le of the thigh. 



To and including July 17, or for the first ten days, there were small, 

 hard swellings at the i)ointof iiu)culation,l)ut no positive signs of disease, 

 and the a[)petite remained good. There were considerable variations 

 in the temperatures, but it is doubtful if this had any pathological sig- 



